Sampling valve apparatus



Dec. 16, 1969 R. e. CHAMBERS 3,483,754

SAMPLING VALVE APPARATUS Filed Nov. 8, 1967 INVENTOR Roam? CAM mama BY Mali/91 M48704 v 30051240 ATTORNEYS.

United States Patent 3,483,754 SAMPLING VALVE APPARATUS Robert G. Chambers, Sand Springs, Okla, assignor to Sinclair Research, Inc. Filed Nov. 8, 1967, Ser. No. 681,314 Int. Cl. G011: J/OO US. Cl. 73-422 2 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a sampling apparatus which permits a sample of liquid or gas or a combination of both to be collected in a single phase from a high pressure source, vaporized, and injected into a suitable carrier gas stream for component analyses.

For example, in the analyses of mixtures of volatile components by gas chromatography, a small volume, often at high pressure, of liquid or gas to be tested must be injected into an inert carrier gas, at a lower pressure, prior to introduction into the chromatograph. The apparatus of the present invention permits the high pressure volatile sample to be accurately expanded and reduced in pressure in a few simple steps without the necessity for the application of external heat to effect the expansion and then injected into the carrier gas stream with a minimum of opportunity for the composition of the sample to change in composition. Heat is supplied to assist in vaporizing the sample.

Briefly the apparatus of this invention comprises a single body containing therein a small sample chamber adjacent and connected to a much larger expansion chamber. Samples to be tested are introduced into the sample cham ber through a port in the body. Two additional ports are provided for the entry into and exit from the larger expansion chamber of carrier gas. One end of the sample chamber is sealed by a sample charging valve which also controls the entry of the sample to be tested into the sample chamber through the sample charging port. The

other end of the sample chamber, which is connected to l the larger expansion chamber, is sealed by a second valve. The shaft of this valve passes through the expansion chamber and controls the passage of carrier gases through that chamber.

The apparatus of the invention will be described in more detail by referring to the drawing.

Unit body 1 contains sample chamber 2 and expansion chamber 3 which is approximately 500 times larger than sample chamber 2. Sample charging valve 4 is provided to seal one end 21 of the sample chamber 2 and to control the introduction of the sample into the sample chamber through sample charging port 6. The other end 2" of the sample chamber is sealed by the expansion valve 10, the shaft 5 of which passes through expansion chamber 3. The portion of the expansion valve shaft 5 passing through the expansion chamber is of somewhat smaller diameter than the interior of the chamber itself, thus providing a space between the interior walls of the expansion chamber and the valve shaft. Two carrier gas ports 7 and 8 are provided opposite to each other and connected into the expansion chamber. To O-ring seals 9 on the expansion valve shaft, are placed so that when the expansion 3,483,754 Patented Dec. 16, 1969 valve is closed to seal off the sample chamber, one O-ring is on either side of the carrier gas ports.

In operation, the sample unit is charged by connecting the sample charging port 6 to the fluid sample source and opening the sample charging valve 4 which seals the sample chamber 2. The expansion valve 10 which seals the other end of the sample chamber, is also opened far enough that both O-rings 9 are past the carrier gas ports 7 and 8. A vacuum pump (not shown) is then connected to the gas ports and the system evacuated. Once the air has been removed from the system, the expansion valve is closed so as to seal off the sample chamber from the expansion chamber and the vacuum pump disconnected. The sample source is then opened, filling the sample chamber with the sample. After next closing the sample charging valve to seal off the sample chamber from the samp e source, the sample unit is disconnected from the sample source. The sample in the sample chamber is expanded and reduced in pressure by opening the expansion valve far enough to allow the sample to expand into the expansion chamber but not so far that the O-ring on the sample chamber side of the carrier gas ports passes the ports and permits the sample to escape. Once the carrier gas ports are connected into the carrier gas stream, the carrier gas will flow between the two O-rings around the shaft of the expansion valve. By opening the expansion valve the rest of theway until both O-rings are on the side of the carrier gas ports fartherest from the sample chamber, the carrier gas is allowed to flow through the expansion chamber where the sample is located and thereby transport the vaporized sample to the testing instrument. The entire sample unit is heated by a wrapping with electrical tape, putting it into an air bath or by any other suitable device, so as to bring the sample up to a desired testing temperature and assist in vaporizing the liquid samples, though it is to be understood that it is a feature of this invention that no external source of heat is required to effect the expansion of the sample in the apparatus of this invention.

To further illustrate this invention, the apparatus was used with a gas chromatograph unit to analyze 1) a binary system of 2.0 mol percent C and 80 mol percent nC and (2) a multicomponent hydrocarbon system exhibiting a saturation pressure of 3800 p.s.i.g. The binary system was combined in a PVT cell at 75 F. and 1000 p.s.i.g. Samples were taken at these conditions with the resulting data for the analysis as follows:

MOL PERCENT Original Component composition Test 1 Test 2 C3 20.00 20. 36 20. nCs 80.00 79.64 79. 31

MOL PERCENT Original Component analysis Test 1 Test 2 5. 41 5. 37 5. Q 1. 01 1. 08 l. 0 2. 41 2. 43 2. 43 92 98 98 l. 46 1. 41 1. 417

MOL PERCENT 1 Original Component analysis Test 1 Test 2 Ca 1. 82 l. 86 1. 79 0 24. 93 25. 20 24. 98

The unit was tested for mechanical operation at pressures to 10,000 p.s.i.a. and temperatures to 300 C. At these elevated pressures and temperatures, all component parts operated very well. Also, there was sufiicient carrier gas flow through the expansion chamber to sweep the sample into the chromatograph.

I claim:

1. An apparatus for expanding and vaporizing a fluid for injection of the expanded and vaporized fluid into a carrier gas stream, which comprises, in a single body, a small first chamber and a larger second chamber adjacent to and connected with the first chamber, said first chamber being sealed at the end most remote from the larger chamber by a first valve which also controls the introduction of samples to be tested through a first port leading into said first chamber, and said first chamber being sealed at the end adjacent to and connected with the second, larger chamber, by a second valve, the shaft of which passes loosely through said second chamber, said second chamber being intersected by second and third ports located opposite to one another in the sides of the second chamber, two seal means encircling the shaft of said second valve and engaging the walls of the second chamber in a gas tight manner, and positioned on the shaft so that when the second valve is closed so as to seal the first chamber one seal means will be on either side of the second and third ports and when the second valve is opened both seal means are on the side of said second and third ports remote from the first chamber.

2. The apparatus of claim 1 in which the second chamber is about 500 times as large as the first chamber.

References Cited UNlTED STATES PATENTS 2,534,489 12/1950 Webber et a1. 73-4215 3,166,939 1/1965 Koeller et a1. 3,318,154 5/1967 Rendina.

ROBERT G. NILSON, Primary Examiner US. Cl. X.R. 137-606 

